Joanne Choi, the lead author of the study, says this is important because once the acidity level of the mouth drops below 5.5, the enamel on your teeth starts to demineralise.

"Intraoral pH decreased slowly over the hours of sleep in all participants, but showed greater falls over a longer period of time when participants were forced to mouth breathe," says Choi.

"Our findings support the idea that mouth breathing may indeed be a causal factor for dental diseases such as enamel erosion and caries."

Breathing through your mouth when asleep is one way that we may create an acidic environment for your teeth, but for most people, the main source of acid comes from diet.

The Australian Better Health website lists a number of common foods that raise the acidity in your mouth, including soft drinks, high-sugar lollies, wine, most fruit juices and even lemon-flavoured teas.

Thankfully there are ways you can protect the enamel on your teeth without having to worry about how you breathe when you sleep.

In an article for Choice, food scientist David Oakenfull lists seven ways to keep your mouth on the right side of acidity, such as brushing twice a day, drinking fluoridated water and limiting sugary foods and drinks.